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1 | /* $KAME: if_nameindex.c,v 1.8 2000/11/24 08:20:01 itojun Exp $ */ |
2 | ||
3 | /*- | |
4 | * Copyright (c) 1997, 2000 | |
5 | * Berkeley Software Design, Inc. All rights reserved. | |
6 | * | |
7 | * Redistribution and use in source and binary forms, with or without | |
8 | * modification, are permitted provided that the following conditions | |
9 | * are met: | |
10 | * 1. Redistributions of source code must retain the above copyright | |
11 | * notice, this list of conditions and the following disclaimer. | |
12 | * | |
13 | * THIS SOFTWARE IS PROVIDED BY Berkeley Software Design, Inc. ``AS IS'' AND | |
14 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |
15 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | |
16 | * ARE DISCLAIMED. IN NO EVENT SHALL Berkeley Software Design, Inc. BE LIABLE | |
17 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL | |
18 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS | |
19 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) | |
20 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT | |
21 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY | |
22 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF | |
23 | * SUCH DAMAGE. | |
24 | * | |
25 | * BSDI Id: if_nameindex.c,v 2.3 2000/04/17 22:38:05 dab Exp | |
26 | */ | |
27 | ||
28 | #include <sys/types.h> | |
29 | #include <sys/socket.h> | |
30 | #include <net/if_dl.h> | |
31 | #include <net/if.h> | |
32 | #include <ifaddrs.h> | |
33 | #include <stdlib.h> | |
34 | #include <string.h> | |
35 | ||
36 | /* | |
37 | * From RFC 2553: | |
38 | * | |
39 | * 4.3 Return All Interface Names and Indexes | |
40 | * | |
41 | * The if_nameindex structure holds the information about a single | |
42 | * interface and is defined as a result of including the <net/if.h> | |
43 | * header. | |
44 | * | |
45 | * struct if_nameindex { | |
46 | * unsigned int if_index; | |
47 | * char *if_name; | |
48 | * }; | |
49 | * | |
50 | * The final function returns an array of if_nameindex structures, one | |
51 | * structure per interface. | |
52 | * | |
53 | * struct if_nameindex *if_nameindex(void); | |
54 | * | |
55 | * The end of the array of structures is indicated by a structure with | |
56 | * an if_index of 0 and an if_name of NULL. The function returns a NULL | |
57 | * pointer upon an error, and would set errno to the appropriate value. | |
58 | * | |
59 | * The memory used for this array of structures along with the interface | |
60 | * names pointed to by the if_name members is obtained dynamically. | |
61 | * This memory is freed by the next function. | |
62 | * | |
63 | * 4.4. Free Memory | |
64 | * | |
65 | * The following function frees the dynamic memory that was allocated by | |
66 | * if_nameindex(). | |
67 | * | |
68 | * #include <net/if.h> | |
69 | * | |
70 | * void if_freenameindex(struct if_nameindex *ptr); | |
71 | * | |
72 | * The argument to this function must be a pointer that was returned by | |
73 | * if_nameindex(). | |
74 | */ | |
75 | ||
76 | struct if_nameindex * | |
77 | if_nameindex(void) | |
78 | { | |
79 | struct ifaddrs *ifaddrs, *ifa; | |
80 | unsigned int ni; | |
81 | int nbytes; | |
82 | struct if_nameindex *ifni, *ifni2; | |
83 | char *cp; | |
84 | ||
85 | if (getifaddrs(&ifaddrs) < 0) | |
86 | return(NULL); | |
87 | ||
88 | /* | |
89 | * First, find out how many interfaces there are, and how | |
90 | * much space we need for the string names. | |
91 | */ | |
92 | ni = 0; | |
93 | nbytes = 0; | |
94 | for (ifa = ifaddrs; ifa != NULL; ifa = ifa->ifa_next) { | |
95 | if (ifa->ifa_addr && | |
96 | ifa->ifa_addr->sa_family == AF_LINK) { | |
97 | nbytes += strlen(ifa->ifa_name) + 1; | |
98 | ni++; | |
99 | } | |
100 | } | |
101 | ||
102 | /* | |
103 | * Next, allocate a chunk of memory, use the first part | |
104 | * for the array of structures, and the last part for | |
105 | * the strings. | |
106 | */ | |
107 | cp = malloc((ni + 1) * sizeof(struct if_nameindex) + nbytes); | |
108 | ifni = (struct if_nameindex *)cp; | |
109 | if (ifni == NULL) | |
110 | goto out; | |
111 | cp += (ni + 1) * sizeof(struct if_nameindex); | |
112 | ||
113 | /* | |
114 | * Now just loop through the list of interfaces again, | |
115 | * filling in the if_nameindex array and making copies | |
116 | * of all the strings. | |
117 | */ | |
118 | ifni2 = ifni; | |
119 | for (ifa = ifaddrs; ifa != NULL; ifa = ifa->ifa_next) { | |
120 | if (ifa->ifa_addr && | |
121 | ifa->ifa_addr->sa_family == AF_LINK) { | |
122 | ifni2->if_index = | |
123 | ((struct sockaddr_dl*)ifa->ifa_addr)->sdl_index; | |
124 | ifni2->if_name = cp; | |
125 | strcpy(cp, ifa->ifa_name); | |
126 | ifni2++; | |
127 | cp += strlen(cp) + 1; | |
128 | } | |
129 | } | |
130 | /* | |
131 | * Finally, don't forget to terminate the array. | |
132 | */ | |
133 | ifni2->if_index = 0; | |
134 | ifni2->if_name = NULL; | |
135 | out: | |
136 | freeifaddrs(ifaddrs); | |
137 | return(ifni); | |
138 | } | |
139 | ||
140 | #ifndef __OpenBSD__ | |
141 | void | |
142 | if_freenameindex(struct if_nameindex *ptr) | |
143 | { | |
144 | free(ptr); | |
145 | } | |
146 | #endif |